Videoconferencing enables individuals located remote from each other to have face-to-face meetings on short notice using audio and video telecommunications. A videoconference can involve as few as two sites (point-to-point) or several sites (multi-point). A single participant may be located at a conferencing site or there may be several participants at a site, such as at a conference room. Videoconferencing can also be used to share documents, information, and the like.
Participants in a videoconference interact with participants at other sites via a videoconferencing endpoint. An endpoint is a terminal on a network, capable of providing real-time, two-way audio/visual/data communication with other terminals or with a multipoint control unit (MCU, discussed in more detail below). An endpoint may provide speech only; speech and video; or speech, data and video communications, etc. A common videoconferencing endpoint comprises a display unit on which video images from one or more remote sites can be displayed. Exemplary endpoints can include Polycom VSX series, HDX series, etc. (each available from Polycom, Inc.). The videoconferencing endpoint sends video and/or data from a local site to the remote site(s) and displays video and/or data received from the remote site(s) on a screen.
Video images displayed on a screen at a videoconferencing endpoint can be arranged in a layout. The layout may include one or more allocated areas (segments) for displaying video images. A segment can be a portion of the screen of a receiving endpoint that is allocated to a video image received from one of the sites participating in the session. For example, in a videoconference between two participants, a segment can cover the entire display area of the screen of the local endpoint. Another example can be in a video conference between a local site and multiple other remote sites if the videoconference is conducted in switching mode, i.e., such that video from only one other remote site is displayed at the local site at a single time and the displayed remote site can be switched, depending on the dynamics of the conference. In contrast, in a continuous presence (CP) conference, a conferee at a terminal can observe, simultaneously, several other participants' sites in the conference. Each site may be displayed in a different segment of the layout, wherein each segment may be the same size or a different size. The choice of the sites displayed and associated with the segments of the layout may vary among different conferees that participate in the same session. In a continuous presence (CP) layout, a received video image from a site can be scaled down in order to fit a segment size.
A multipoint control unit (MCU) can be used to manage a video communication session (i.e., a videoconference). An MCU is a conference controlling entity that can be located in a node of a network or in a terminal, which can receive and process several media channels, from access ports, according to certain criteria and distributes them to the connected channels via other ports. Examples of MCUs include the MGC-100 and RMX 2000 (available from Polycom Inc.). Some MCUs are composed of two logical units: a media controller (MC) and a media processor (MP). A more thorough definition of an endpoint and an MCU can be found in the International Telecommunication Union (“ITU”) standards, such as but not limited to the H.320, H.324, and H.323 standards. Additional information regarding the ITU standards can be found at the ITU website www.itu.int.
To present a video image within an allocated area (a segment) over a screen (a layout) of a receiving endpoint (site), the entire received video image can be manipulated, scaled down and displayed or a portion of the video image can be cropped by the MCU and be displayed, for example. An MCU can crop lines or columns from one or more edges of a received conferee video image in order to fit it to the area of a segment in the layout of the videoconferencing image. Another cropping method may crop the edges of the received image according to a region of interest in the image, as disclosed in U.S. patent application Ser. No. 11/751,558, the entire contents of which are incorporate herein by reference.
In a videoconferencing session the size of a segment in a layout may be defined according to a layout selected, by a conferee for example, to be used in the session. For example in a 2×2 layout, each segment is in the size of substantially a quarter of the display as illustrated in FIG. 1. Layout 100 includes segments 112, 114, 116 and 118. In a 2×2 layout if five sites are taking part in a session, conferees at each site can see the other four sites.
In the example illustrated in FIG. 1, at a certain period of time only three quarters of the area of the display is used—segments 112, 114, and 116—while the fourth quarter 118 is occupied by a background color, for example. Such a situation may occur when only four sites are active and each site sees the other three. Furthermore, segment 112 displays an empty room, while the sites presented in segment 114 and 116 each include a single conferee 130. Consequently during this period of the session only half of the screen area is effectively used and the other half is ineffectively used. The area of segment 118 and segment 112 do not contribute to the conferees' experience and therefore are not exploited in a smart and effective manner.
Furthermore as can be seen in both segment 114 and 116, a major area of the image is redundant. In other words, the video images capture a large portion of the room while the conferees' images 120 and 130 are small and located in a small area. In those cases as in many other examples a significant portion of the display area is wasted on uninteresting areas. Consequently, the area that is captured by the conferees' images is affected and the experience of the conferees viewing the layout of the video conference is poor.
Moreover, there are conference sessions in which one or more sites have a single participant, while in other sites there are two or more participants. In currently available layouts, each site receives similar segment sizes and as a result, each participant at a site with a plurality of conferees is displayed over a smaller area than a conferee in a site with less participants, degrading the experience of the viewer.
If during a conference call one of the conferees steps far from the camera, that conferee's image will seem smaller and again the experience of the conferees viewing the layout of the video conference is degraded. Likewise, if the conferees at a displayed site leave the room for a certain time and return afterward, the empty room is displayed on the layout during the conferees' absence.
In some known techniques the viewing conferees at the other sites can manually change the layout viewed at their endpoints to adjust to the dynamics of the conference. Changing the layout can be done manually by the conferees, but this requires the conferees to stop what they are doing and deal with a layout menu to make such an adjustment, for example.